Electronic Theses and Dissertation

Survei metode gravitasi telah dilakukan untuk memprediksi sebaran anomali gravitasi di kawasan pemukiman Ujung Pancu, Kecamatan Peukan Bada, Kabupaten Aceh Besar, Provinsi Aceh. Data percepatan gravitasi diukur dengan Gravitymeter CG-5 Autograv Scientrex. Pengukuran data dilakukan secara grid pada 253 stasiun yang terdistribusi merata dengan jarak antara tiap stasiun sejauh 50 m, di area seluas 2x1 km persegi. Data yang diperoleh berupa nilai percepatan gravitasi, kemudian dilakukan beberapa koreksi standar seperti koreksi lintang, koreksi kelelahan alat, koreksi pasang surut, koreksi udara bebas, koreksi Bouguer, dan koreksi terrain, sehingga diperoleh nilai anomali Bouguer lengkap. Nilai anomali Bouguer lengkap merupakan gambaran dari variasi nilai densitas material penyusun di bawah permukaan. Berdasarkan nilai anomali Bouguer lengkap diketahui bahwa kawasan penelitian memiliki nilai percepatan gravitasi yang berkisar antara 61.34 mGal sampai 66.04 mGal. Sebaran anomali dengan nilai tinggi terdistribusi pada bagian Utara dan Barat Daya kawasan penelitian. Sedangkan kawasan dengan nilai sebaran anomali rendah terdistribusi mulai dari bagian tenggara dan pada bagian tengah. Nilai anomali Bouguer lengkap selanjutnya dilakukan pemisahan antara anomali regional dengan anomali residual, hal ini dilakukan untuk memperjelas bentuk dari distribusi nilai percepatan gravitasi pada kawasan penelitian. Berdasarkan peta anomali residual yang menggambarkan sebaran nilai anomali gravitasi pada daerah dangkal, pada kawasan dengan nilai distribusi nilai anomali percepatan gravitasi rendah terlihat seperti membentuk aliran yang memanjang menuju ke kawasan tepi pantai, hal tersebut diasumsikan bahwa adanya bekas aliran sungai pada kawasan penelitian. hal ini juga diperkuat oleh kondisi di sekitar kawasan penelitian, dimana pada beberapa kawasan terlihat adanya tambak ikan dan aliran sungai pada kawasan tersebut.

A gravity method survey has been carried out to predict the distribution of gravity anomalies in the Ujung Pancu residential area, Peukan Bada Sub-District, Aceh Besar, Aceh Province. Gravity acceleration data was measured with the Gravitymeter CG-5 Autograv Scientrex. Data measurements were carried out grids at 253 stations which were evenly distributed with a distance between each station of 50 m, in an area of 2x1 square km. The data obtained is in the form of the value of gravitational acceleration, then several standard corrections are made such as latitude correction, drift correction, tidal correction, free air correction, Bouguer correction, and terrain correction, so that a complete Bouguer anomaly value is obtained. The complete Bouguer anomaly value is an illustration of the variation in the density value of the subsurface material. Based on the complete Bouguer anomaly values, it is known that the research area has gravitational acceleration values ranging from 61.34 mGal to 66.04 mGal. The distribution of anomalies with high values is distributed in the North and Southwest of the study area. While the areas with low anomaly distribution values are distributed starting from the southeast and in the central part. The complete Bouguer anomaly value is then separated between the regional anomaly and the residual anomaly, this is done to clarify the shape of the distribution of the gravitational acceleration values in the research area. Based on the residual anomaly map which illustrates the distribution of gravity anomaly values in shallow areas, in areas with low gravity anomaly distribution values it looks like it forms a stream that extends towards the waterfront area, it is assumed that there is a former river flow in the study area. This was also reinforced by the conditions around the research area, where in several areas fish ponds and rivers were visible in the area.